From owner-chemistry@ccl.net Thu Nov 18 19:00:01 2021 From: "Tatiana Korona tania=-=tiger.chem.uw.edu.pl" To: CCL Subject: CCL: Why on increasing the SCF maxiter, the undesired modes vanish? Message-Id: <-54504-211118185432-14378-686qoid1V3O/umZj7paZPg . server.ccl.net> X-Original-From: Tatiana Korona Content-Type: MULTIPART/MIXED; BOUNDARY="1473576194-1021197345-1637279662=:31709" Date: Fri, 19 Nov 2021 00:54:22 +0100 (CET) MIME-Version: 1.0 Sent to CCL by: Tatiana Korona [tania-,-tiger.chem.uw.edu.pl] This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --1473576194-1021197345-1637279662=:31709 Content-Type: TEXT/PLAIN; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Mariusz, it is interesting, however, why the program does not stop after=20 nonconverged SCF. I do not use Orca, but shouldn't it produce at least a=20 warning? Best wishes, Tatiana On Wed, 17 Nov 2021, Mariusz Rado=C5~D mariusz.radon++uj.edu.pl wrote: > > Sent to CCL by: =3D?utf-8?B?TWFyaXVzeiBSYWRvxYQ=3D?=3D [mariusz.radon-#-u= j.edu.pl] > > >> On 17 Nov 2021, at 07:15, SUMANGLA ARORA arorasumangla[#]gmail.com wrote: >> >> >> Sent to CCL by: "SUMANGLA ARORA" [arorasumangla~~gmail.com] >> Dear All, >> I am using Orca for calculations. I am getting too many imaginary modes = in >> transition state when running numfreq with lower SCF maxiter (error >> termination in SCF). However, when I increase SCF maxiter, I am getting = only >> one imaginary mode. >> Can you please explain why on increasing the SCF maxiter, the undesired = modes >> vanish? >> >> >> Thanks >> Sumangla >> > > Dear Sumangla: > > You already answered your question: this is because with the lower SCF ma= xiter you are not able to converge the SCF (you mentioned error termination= in SCF). If the SCF procedure is not properly converged, the =E2=80=9Cfreq= uencies=E2=80=9D (and all other properties) obtained afterwards are rubbish= =2E.. they are totally unreliable and you should not give them any physical= significance. > > Best wishes, > Mariusz > > > > > --=20 > Mariusz Radon, Ph.D., D.Sc. > Assistant Professor > Faculty of Chemistry, Jagiellonian University > > Address: Gronostajowa 2, 30-387 Krakow, Poland > Room C1-06, Phone: 48-12-686-24-89 > E-mail: mradon/./chemia.uj.edu.pl (mariusz.radon/./uj.edu.pl) > Web: https://tungsten.ch.uj.edu.pl/~mradon > ORCID: https://orcid.org/0000-0002-1901-8521 > > > > -=3D This is automatically added to each message by the mailing script = =3D-> > Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/tania.html Quantum Chemistry Laboratory, University of Warsaw, Pasteura 1, PL-02-093 W= arsaw, POLAND --1473576194-1021197345-1637279662=:31709--